The present invention relates to power control circuits and, more particularly, to a novel circuit for controlling the magnitude of voltage applied to, and current flowing through, a load.
It is often useful to be able to control the voltage applied across a load for the purposes of controlling the flow of current through that load. As an example, in microwave ovens, wherein the amount of microwave power supplied by a magnetron, and the like generators, must be varied to facilitate different cooking schedules, it is desirable to be able to turn the microwave generator load to the power-producing condition with a variable duty cycle. To prevent abnormal wear of mechanical components utilized to switch primary power to the load power supply transformer, it is desirable to have the power supply transformer remain in the energized condition throughout the cooking procedure, and to control the percentage of time during which the load is enabled during each unit of time, to establish the heating energies supplied by the microwave generator load on the power supply.